Field of the Invention
The present invention relates to a wireless communication technique.
Description of the Related Art
A mechanism capable of providing various services according to the distance between devices has been developed by utilizing a communication technique for realizing low energy consumption and long-distance communication, among communication techniques for allowing devices to communicate directly with each other. As an example of such a communication technique, there is a technique termed Bluetooth (registered trademark) low energy (BLE).
For example, a mechanism using BLE is iBeacon (registered trademark). In this mechanism, first, a sender sends a signal termed a beacon, which includes device information of the sender, by broadcasting using BLE. Then, a receiver can provide various services using the device information included in the received signal and distance information obtained based on the intensity of the signal. Using this mechanism, for example, if a certain store sends a beacon signal and a mobile terminal of a customer detects the signal from the store, it is possible to provide the service of notifying the customer of sales information according to the distance between the mobile terminal and the store.
Additionally, as the conventional art for informing a user of the distance between terminals, Japanese Patent Application Laid-Open No. 2013-236255 discusses a technique using both of wireless communication, and an ultrasonic signal generator and an ultrasonic signal receiver of terminals.
There are various possible applications of the above mechanism using a signal via wireless communication such as BLE. For example, if a user needs to be authenticated to enter an office, the user always carries around a security card or a mobile terminal. If a sender for sending a signal such as a beacon signal is mounted on such a security card or a mobile terminal, it is possible to grasp the position of the user and provide various services according to the position of the user.
However, constantly sending a signal directly or indirectly related to a user coming from and going into an area where the user is required to be authenticated from a security card or a mobile terminal of the user raises concerns about security risks even if information of the signal is encrypted.